Module II: Ventilation Flashcards
Ventilation
Mechanical process by which ambient air is brought into and exchanged with air in the lungs
Respiration
Gas exchange that occurs in lungs (at alveolar/capillaries) and throughout the body (at target tissue/capillaries)
The mechanical process by which ambient air is brought into and exchanged with air in the lungs is ________.
Ventilation
Gas exchange that occurs in lungs (at alveolar/capillaries) and throughout the body (at target tissue/capillaries) is called _____________.
Respiration
Ventilation Rate
breaths per minute
~12/min at rest
Alveolar Ventilation
Volume of air that reaches the alveoli per minute
4.5 L/min
Dead Space Ventilation
Volume of air that DOES NOT reach the alveoli per minute
Minute Ventilation
volume of air inspired/expired per minute
6 L/min at rest
______ + ______ = minute ventilation
Alveolar ventilation
Dead Space Ventilation
What are the two respiratory centers in the brainstem?
Medulla
Pons
What is the action and function of the dorsal respiratory group in the medulla (DRG)?
Action: primarily inspiratory
Function: sets automatic rhythm of breathing
CO2 and O2 levels influence the rate of ventilation through which respiratory center?
DRG
Dorsal Respiratory Group in medulla
What kind of muscles would the DRG influence/control?
Inspiratory muscles:
- -> external intercostal muscles
- -> diaphragm
What is the action and function of the ventral respiratory group in the medulla (VRG)?
Action: both inspiratory and expiratory actions
Function:
- quiet during rest
- active when increased ventilation is required
Does the VRG control the internal intercostals or the external intercostals?
Internal intercostals
What is the function of the pneumotaxic and apneustic centers in the pons?
To fine tune the actions from the VRG and DRG
Modifying depth and rate of inspiration already set by VRG and DRG
What are the 3 groups of neurons in the medulla and pons that control contraction and relaxation of respiratory muscles?
- DRG in medulla
- VRG in medulla
- Pneumotaxic and apneustic centers in pons
Where do lung receptors send their impulses to?
The DRG to influence rate of ventilation
What are the 3 types of lung receptors?
- Irritant receptors
- Stretch receptors
- J-receptors (Juxtapulmonary capillary receptors)
Where are irritant receptors usually located?
In the epithelium of conduction airways in larger airways…not distal
What are some stimulants of an irritant receptor?
Noxious gas
Particles
What is the action of an irritant receptor?
- Cough reflex
- Initiate bronchoconstriction of airway
- Increase ventilation rate via DRG
Where are stretch receptors located?
In smooth muscle of conducting airways
What are the stimulants of stretch receptors?
For:
- Adults: It takes a lot to activate these
Occurs at extremes of tidal volume
(max volume)
- Newborns: Plays a role in maintaining ventilation
–> termed: Hering-Breuer Expiratory Reflex
What is the action of stretch receptors?
They DECREASE ventilation (rate and volume) via DRG
Where are J-receptors located?
alveolar septum of capillaries
What is the stimulus for J-receptors?
Elevated pulmonary capillary pressure
What is the action produced by J-receptors?
Rapid, shallow breathing
Also influence CV system by:
–> decreasing HR
–> decreasing BP
What are the two types of chemoreceptors and what do they monitor?
- Central chemoreceptors
- Peripheral chemoreceptors
Both monitor pH, PaCO2, and PaO2
Fill in the blanks:
Central chemoreceptors indirectly monitor _____ of arterial blood (_____) by monitoring ____ of ____.
Central chemoreceptors indirectly monitor CO2 LEVELS of arterial blood (PaCO2) by monitoring PH of CSF.
What stimulates central chemoreceptors?
Changes in pH levels in CSF
